1. Get a Blood Value
Start by getting your vitamin D blood level measured. This is essential because it will give you a baseline measurement that will dictate the amount of vitamin D you should take. For example, if you have are very deficient, it's recommended you use a dosing system to raise vitamin D levels.

Once levels are within "adequate" range, a maintenance dose that is smaller can be used.

2. How to Get Vitamin D Measured
Your doctor should be able to measure your vitamin D. It is covered by most insurance companies, so getting it measured should not be difficult. If you don’t have insurance or prefer to get your test done privately, various lab testing companies can measure vitamin D for you. Independent tests range in price from $12 to $40 in most countries.

Because the body makes vitamin D in response to sunlight, levels often vary seasonally due to differences in the amount of sun you are exposed to. It's good practice to test your vitamin D level seasonally, every three months. Doing so will give you raw data to adjust the dosage much more effectively.

For some physiological reason yet to be fully explained by science, a large bolus dose twice a week seems to work better for raising vitamin D status than taking the same dose divided over 7 days.

In other words, taking 35,000 IUs twice a week works better than 5,000 IUs every day for 7 days. Interestingly, the biweekly bolus dose appears to be more effective than even a much larger daily dose such as 10,000 IUs every day for 7 days.

4. Adjust Vitamin D Intake According to Blood Tests
It’s essential that you test your vitamin D before taking high doses. Vitamin D toxicity is very rare, but we know that it does occur, with negative health effects. Errors in supplementation are the most common cause, indicating the importance of a reputable supplement provider and a reliable physician.

Take note that in all of the cases of toxicity, participants simply needed to discontinue vitamin D intake, symptoms were reversed and health status returned to pre-overdose levels.

5. Test Magnesium and Zinc Too For Best Results
It is a wise practice to measure red blood cell levels of magnesium and zinc at the same time that you test your vitamin D. These are essential minerals, and low levels of either will lead to poor health and a vast array of complications including endocrine imbalance, insomnia, anxiety, and poor energy. If you do not rapidly replenish vitamin D levels from the above dosing protocol, it may be helpful to increase your intake of magnesium, zinc, and vitamin E, either through diet or supplementation.

Zinc is particularly important for optimal testosterone levels, and it is synergistic to all nutrients, meaning increasing your zinc intake can help you elevate your blood vitamin D status.

Adequate magnesium is critical for calcium and vitamin D absorption, which is the reason magnesium deficiency, may hinder vitamin D processing and effectiveness in the body. Additionally, there is evidence of a relationship linking low vitamin D with low vitamin E, especially in special populations such as pregnant women or the elderly.